The invention relates to methods and apparatus for providing clock signals to the various clock using locations of a digital computer.
In the past, in synchronous computers, the object of the clock circuitry has been to clock all the clock-using locations at the same instant in time, known as "T.sub.o ", as nearly as possible. Each clock-using location has a clocking window within which the clock signal can arrive and still enable the associated logic circuit to function. Optimally, the clocking point will be centered in the clocking window of the circuit. However, due to various factors, such as normal process variations in the manufacture of semiconductor devices and printed circuit boards and design inacuracies, T.sub.o may be at the center of the clocking window or may be near to one or the other of the extremities of the window. If T.sub.o is near to one of the window extremities, a transient of one sort or another within the circuit can move the clock pulse outside of the clocking window and cause the logic device associated with the clocked input to fail.